Rotary furnace having a planetary cooler

ABSTRACT

A rotary tube furnace has a number of cooling tubes arranged in planetary manner about the periphery of the furnace, each of the cooling tubes terminating in an inlet head which is inclined outwardly relative to the axis of rotation of the furnace and which communicates with the furnace via an inlet tube which is inclined against the direction of rotation of the furnace.

D United States Paten 1191 1111 3,920,381

Heinemann [45] Nov. 18, 1975 [5 ROTARY FURNACE HAVING A 3,556,495 1/1971 Jensen 432/80 PLANETARY COOLER 313332? 31333 ifi i iii/S8 e1 Inventor: o Heinemann, nig 3,811,824 5/1974 Theil 432/80 Germany 3,813,211 5/1974 Gommesen 432/80 Assigneez polysius AG Neubeckum, Germany 3,829,282 8/1974 Deussner 432/80 [22] Filed: Dec. 26 1973 FORElGN PATENTS OR APPLICATIONS [21] A l N 428 459 645,407 5/1937 Germany 285/183 Primary Examiner-John J. Camby [30] Foreign Application Priority Data Assistant Examiner-Henry C. Yuen Feb. 1, 1973 Germany .1 2304945 f & Mccunoch 52 us. c1. .Q 432/80 57 ABSTRACT [51] Int. Cl. F27D 15/02 A rotary tube furnace has a number of cooling tubes [58] Field of Search 432/80-83,

arranged in planetary manner about the periphery of 432/103-106, l15-117, 26, 45, 34/127, 129, h fu h fth b 165/88 285/183 t e mace, eac 0 t e coo mg tu es terminat ng in an inlet head WhlCh is inclined outwardly relative to the axis of rotation of the furnace and which commu- [56] References cued nicates with the furnace via an inlet tube which is in- UNITED STATES PATENTS clined against the direction of rotation of the furnace. 3,372,915 3/1968 Jensen 432/83 3,502,139 3/1970 Andersen 432/83 11 Claims, 2 Drawing Flgules US. Patent Nov. 18, 1975 Sheet 1 012 3,920,381

U.S..Patent Nov. 18, 1975 Sheet 2 of2 3,920,381

Fig. 2

ROTARY FURNACE HAVING A PLANETARY COOLER This invention relates to a planetary cooler comprising a number of cooling tubes disposed in planetary manner on the periphery of a rotary tube furnace and which are connected to the material exit end of the rotary tube furnace through inlet pipes and inlet heads. The pipes are outwardly inclined against the direction of rotation of the furnace and each inlet head is inclined towards the rotary tube furnace.

In a known planetary cooler of the general type referred to above the cylindrical wall of the cooling tube inlet head is parallel to the furnace axis on the side opposite the inlet tube. The inlet tubes have over their entire length a constant inclination to the furnace axis, and have their axes offset relative to the cooling tube axis in the direction of rotation of the furnace. The inlet tube in this construction projects relatively deeply into the cooling tube inlet head.

Because of these constructional features there is a risk with the known planetary cooler that material may accumulate in the area of the inlet head and cannot flow away fast enough as the furnace turns, and hence is partly fed back into the rotary tube furnace. However, if an attempt'is made by suitably large dimensioning of the inlet head to feed the material more rapidly, the inner wall of the inlet head is insufficiently protected at the place where the hot material dropping through the inlet tube lands, and hence is subject to very rapid wear. A further disadvantage with the known planetary cooler is that the wall of the inlet tube also comes into strongly erosive contact with the hot material dropping through the inlet tube, which leads to frequent maintenance and repair work.

, The object of the invention is therefore to avoid these defects of the known construction by constructing a planetary cooler in such manner that return of material from the inlet head of the cooling tubes into the rotary tube furnace is prevented, and the walls of the inlet headand inlet tubes are particularly well protected from wear.

According to the invention this object is achieved by the combination of the following features:

a. The inlet tubes consist of a shorter part adjacent the rotary tube furnace and extending generally radially therefrom, and a longer part adjacent thereto and outwardly inclined against the direction of rotation of the furnace;

b. the axis of the inclined part of the inlet tube intersects the axis of the inlet head; c. the wall of the cooling tube inlet head facing away from the rotary tube furnace and opposite the mouth of the inlet tube is also inclined to theaxis of rotation of the rotary tube fumace.

Because of the inclination of the inlet tube in accordance with feature (a) the hot material when falling through the inlet tube hardly comes into contact with theinlet tube wall. The wear in this area is thus reduced to a minimum. I

Since the axis of the inclined part of the inlet tube intersects the axis of the inlet head (feature (b), and the cooling tube inlet head wall opposite the mouth of the inlet tube (like the inlet head wall facing the rotary tube furnace)-is inclined to the axis of the furnace, the

tects the inlet head wall from wear at this particularly emperilled point of impact of the hot material. With the rotary movement of the planetary cooler the material is conveyed with a tumbling movement (rather like the gyrowheel principle) through the inclined inlet head into the adjacent main part of the corresponding cooling tube. The inclination of the inlet head wall in the entire peripheral area (i.e. including the side remote from the rotary tube furnace) thus ensures a safe and non-returning flow of material from the inlet head, and also involves intensive cooling on the relatively long path within the inlet head. In a planetary cooler in accordance with the invention, the inlet head of the individual cooling tubes thus may be considered part of the material fed through the inlet tube drops to about the V centre of a trough-shaped recess, wherein consequently a cushion of material can form which effectively proactual cooling tubes.

Because of the inclined arrangement of the inlet head, at the end of each rotation (i.e. shortly before new hot material reaches the inlet head through the inlet tube) a small portion of the material in movement in the inlet head flows back into the above-mentioned trough (below the mouth of the inlet tube) and hence forms the necessary cushion for the fresh hot material arriving. The inclined arrangement of the inlet head prevents any appreciable part of the cushioning material from flowing back into the rotary tube furnace during the rotary movement.

One embodiment of the invention is shown in the drawings wherein:

FIG. 1 is a schematic cross-section through part of a planetary cooler constructed in accordance with the invention; and

FIG. 2 is a partial longitudinal section on the line IIII of FIG. 1.

At the periphery of a rotary furnace 1 is disposed a number of cooling tubes 2 connected to the material outlet end of the rotary tube fumace 1 by ducts, each of which includes an inlet tube 3. Each of these inlet tubes consists of a shorter part 4 adjacent the rotary tube furnace 1 and extending generally radially, with a longer part 6 adjacent thereto and outwardly inclined against the direction of rotation of the furnace (arrow 5). The axis of the radially extending part 4 is indicated by 7, while 8 indicates the axis of the inclined part 6.

Joining each cooling tube 2 with its associated inlet pipe 3 is a substantially cylindrical inlet head 9 having a longitudinal axis 10. The axis 10 of each inlet head 9 is inclined to the longitudinal axis 11 of the cooling tube at an angle which lies between 20 and 45, and preferably between about 30 35. In this way the wall 9' of inlet head 9 which faces the rotary furnace 1 and through which the inlet tube 3 passes, is inclined to the axis of rotation 13 of the rotary tube furnace. Further, the wallv9' of inlet tube 9 remote from the furnace and opposite the mouth of the inlet tube 3 also is inclined to the axis 13 of the furnace and in the direction of movement of the material.

I The axis 8 of the inclined part 6 of the inlet tube 3 intersects the axis 10 of the inlet head. The axis 7 of the generally radial part 4 of each individual inlet tube is offset by an angle B (lying between 5 and 20, preferably about 10) in the direction of rotation of the furnace in relation to a plane 12 which passes through the longitudinal axis 13 of rotary tube furnace and the axis 10 of the inlet head 9.

The height H of the wall of the cooling tube inlet head 9 disposed between the mouth of the inlet tube 3 and the cylindrical main part of cooling tube 2 is between l5 35%, and preferably about 25%, of the in- 3 ternal diameter D of the cooling tube 2.

The terminal end wall 14 of inlet head 9 is externally domed, which firstly facilitates lining with brickwork and secondly helps to ensure that on rotary movement of the planetary cooler the material remaining in inlet head 9 is carried into the trough lying below the mouth of the inlet tube 3, so that a desirable cushion of material 15 is formed.

During rotation of the tube furnace 1, material 16 flows out of the furnace in the manner shown schematically in FIG. 1, through an inlet tube 3, and into the inlet head 2 of the corresponding cooling tube, whereby the wall of the inlet tube is scarcely touched, due to the bend in the inlet tube. The new material dropping into the inlet head falls on the previously mentioned cushion of material 15 in the lowest trough of the inlet head, and during further rotation of the planetary cooler is conveyed into the corresponding cooling tube by a tumbling movement (schematically indicated in FIG. 2 by the line 17).

What is claimed is:

1. In a rotary tube furnace rotatable in one direction about an axis and having a material discharge end, the combination of a planetary cooler comprising a number of cooling tubes disposed in planetary manner about the periphery of said furnace with their longitudinal axes substantially parallel to the axis of rotation of said furnace; and duct means corresponding in number to the number of said cooling tubes and joining the discharge end of said furnace and each of said cooling tubes, each of said duct means comprising an inlet pipe and a head, closed at one end, said inlet pipe being joined at one of its ends to said furnace and at its other end to the closed end of said head, said head being joined at its other end to the associated cooling tube, said inlet pipe having a portion thereof inclined against the direction of rotation of said furnace, and said head having a substantially cylindrical portion inclined outwardly to the longitudinal axis of the associated cooling tube along a line extendingfrom the juncture of said head and the associated tube to the juncture of said head and the associated inlet pipe, said portion extending a sufficient distance whereby material discharged from said furnace through any of said inlet pipes will form a cushion of material at the closed end of the associated head adjacent such inlet pipe.

2. A construction according to claim 1 wherein each inlet pipe has a second portion interposed between said inclined portion and said furnace and which extends 4 substantially radially of the axis of rotation of said furnace.

3. A construction according to claim 1 wherein each head is substantially cylindrical and is inclined to the axis of the associated cooling tube at an angle of between about 20 and 45.

4. A construction according to claim 3 wherein said angle is between about 30 and 35.

5. A construction according to claim 1 wherein the height of said wall between the associated inlet pipe to the associated cooling tube is between about 15% and 35% of the diameter of the associated cooling tube.

6. A construction according to claim 5 wherein said height is about 25% of said diameter.

7. A construction according to claim 1 wherein said head has an externally domed end wall at said closed end.

8. A construction according to claim 1 wherein said head has a longitudinal axis and wherein the inclination of said inlined portion of each of said inlet pipes is between about 5 and 20 to a plane passing through the axis of rotation of said furnace and the axis of the associated head.

9. A construction according to claim 8 wherein said inclination is about 10.

10. A rotary tube furnace rotatable in one direction about an axis; a number of cooling tubes disposed in planetary manner about the periphery of said furnace with their longitudinal axes substantially parallel to the axis of rotation of said furnace; a head at one end of each of said cooling tubes and in communication therewith, each of said heads comprising a substantially cylindrical tube portion closed at one end and joined at its other end to the associated cooling tube and extending from said other end at an outward inclination to the axis of rotation of said furnace; and an inlet tube interconnecting and establishing communication between said furnace and each of said heads, said cylindrical tube portion of each of said heads extending a sufficient distance that material discharged from said furnace into such head via the associated inlet tube will form a cushion of material at the closed end of such head adjacent the associated inlet tube.

11. A construction according to claim 10 wherein each of said inlet tubes has a longitudinal axis which is inclined against the direction of rotation of said fur- 

1. In a rotary tube furnace rotatable in one direction about an axis and having a material discharge end, the combination of a planetary cooler comprising a number of cooling tubes disposed in planetary manner about the periphery of said furnace with their longitudinal axes substantially parallel to the axis of rotation of said furnace; and duct means corresponding in number to the number of said cooling tubes and joining the discharge end of said furnace and each of said cooling tubes, each of said duct means comprising an inlet pipe and a head, closed at one end, said inlet pipe being joined at one of its ends to said furnace and at its other end to the closed end of said head, said head being joined at its other end to the associated cooling tube, said inlet pipe having a portion thereof inclined against the direction of rotation of said furnace, and said head having a substantially cylindrical portion inclined outwardly to the longitudinal axis of the associated cooling tube along a line extending from the juncture of said head and the associated tube to the juncture of said head and the associated inlet pipe, said portion extending a sufficient distance whereby material discharged from said furnace through any of said inlet pipes will form a cushion of material at the closed end of the associated head adjacent such inlet pipe.
 2. A construction according to claim 1 wherein each inlet pipe has a second portion interposed between said inclined portion and said furnace and which extends substantially radially of the axis of rotation of said furnace.
 3. A construction according to claim 1 wherein each head is substantially cylindrical and is inclined to the axis of the associated cooling tube at an angle of between about 20* and 45*.
 4. A construction according to claim 3 wherein said angle is between about 30* and 35*.
 5. A construction according to claim 1 wherein the height of said wall between the associated inlet pipe to the associated cooling tube is between about 15% and 35% of the diameter of the associated cooling tube.
 6. A construction according to claim 5 wherein said height is about 25% of said diameter.
 7. A construction according to claim 1 wherein said head has an externally domed end wall at said closed end.
 8. A construction according to claim 1 wherein said head has a longitudinal axis and wherein the inclination of said inlined portion of each of said inlet pipes is between about 5* and 20* to a plane passing through the axis of rotation of said furnace and the axis of the associated head.
 9. A construction according to claim 8 wherein said inclination is about 10*.
 10. A rotary tube furnace rotatable in one direction about an axis; a number of cooling tubes disposed in planetary manner about the periphery of said furnace with their longitudinal axEs substantially parallel to the axis of rotation of said furnace; a head at one end of each of said cooling tubes and in communication therewith, each of said heads comprising a substantially cylindrical tube portion closed at one end and joined at its other end to the associated cooling tube and extending from said other end at an outward inclination to the axis of rotation of said furnace; and an inlet tube interconnecting and establishing communication between said furnace and each of said heads, said cylindrical tube portion of each of said heads extending a sufficient distance that material discharged from said furnace into such head via the associated inlet tube will form a cushion of material at the closed end of such head adjacent the associated inlet tube.
 11. A construction according to claim 10 wherein each of said inlet tubes has a longitudinal axis which is inclined against the direction of rotation of said furnace. 